The WO 2010/070461 A1 discloses a microfluidic device comprising a magneto-capillary valve for liquids having an appreciable surface tension comprising magnetic particles. The device comprises at least two planar solid substrates with a functionalized surface each, wherein at least a first solid substrate has a patterned surface comprising at least two hydrophilic areas separated from one another by at least one hydrophobic area (cf. also Remco C. den Dulk, Kristiane A. Schmidt, Gwénola Sabatté, Susana Liébana, Menno W. J. Prins: “Magneto-capillary valve for integrated purification and enrichment of nucleic acids and proteins”, Lab Chip, 2013, 13, 106).